Although application of electroplate to a metal substrate may be facilitated by roller electroplating process, e.g., as taught in the U.S. Pat. No. 4,661,213, various other types of pad plating equipment have been developed to take advantage of such types of plate application when the metal substrate is in extended form, e.g., a metal wire or metal strip. A pad can carry an electrolyte and be run in a direction of travel of the workpiece, or against the direction of travel of the workpiece. In addition to carrying the electrolyte, the pad should be resistant to the electrolyte, it having been found that Dacron can sometimes be suitable for such application, as disclosed for example in U.S. Pat. No. 3,661,752.
It has also been taught that if an electrolyte zone can be established between anode and cathode, the cathode may be provided by an endless belt, more particularly an endless metal belt as disclosed in U.S. Pat. No. 4,304,653.
However, electroplating wherein a solution is applied to a plating belt for carrying the solution has ostensibly attracted greater attention. In this regard a belt having fabrication similar to a paint roller has been studied. Such a belt can comprise a fabric backing material, such as Dacron or the like, which is secured to a fibrous nap, made for example of Dynel. Such a belt plating apparatus has been disclosed in the U.S. Pat. Nos. 3,951,772, 3,904,489 and 3,966,581.
There has also been investigated the utilization of belts where a depletable anode may be employed. For example, a roller anode can be wrapped in a porous mesh which thereby comes into contact with the strip workpiece. The porous mesh can enhance uniform erosion of the depletable anode roll as it is being sacrificed during electroplating, such as taught in the U.S. Pat. No. 4,416,756.
More recently in the U.S. Pat. No. 4,564,430 there has been disclosed a contact plater for continuously plating a workpiece. The plater employs a continuous loop of material that is inert to the plating solution. A porous covering for absorbing the plating solution can be mounted on the continuous loop.
There is nevertheless a need for improvement to provide a belt plating system having a highly economical operation coupled with extended operation. A plating apparatus should allow for plating at high current densities, yielding a smooth and even deposit. Such plating aspects should desirably be coupled with flexible processing allowing for fast application of carefully controlled electroplate composition.